This would be the best solution, however for most of us, mortals, unreachable with serious, difficult attack (it means also correct distans, not zombi attacking from 10 feet away).
Timespace is so very small, that human brain can't handle it normally.

I think this assumption is the problem. O Sensei, for example, insisted on attacks coming from at least three steps away. His thinking, reportedly, was why let an attacker get closer than that. If someone comes in slower you can back away to maintain proper distance. At any rate, as someone closes the distance to attack they are vulnerable to a kick from Nage. That's why they have to close the distance quickly and if they are smart from a side angle. So the close in short attacks that I think you are worried about only happen when someone sucker punches you or else you are going toe to toe in order to fight them... which you should not be doing if you want to do Aikido as that's not what Aikido is good for. Ideally you want Uke to unbalance himself from the attack. There are ways to encourage this. Once off balance don't let Uke regain his or her balance. Almost all strikes will unbalance Uke at least slightly. Remember, if Uke wants to strike you she will have to come to you. Continue to move to a safe place, like the blind spot slightly behind, and Uke will have to continue to move if she wants to try to hit you. You don't have to throw Uke in one short move. You have infinite options.

The sucker punch short strike is difficult to deal with but there are ways, nonetheless, to avoid being struck, lead, and blend Uke off balance even with such a strike. It's not hypothetical. I was taught to deal with these strikes by many Sensei's over many years and continue to train in this manner with more advanced students. Body positing, timing, leaving, joining, these are always relevant and useful. If you are tempted by this difficult situation to stop the attack and then try to move or unbalance Uke, then the usual problems with not leading Uke off balance present themselves... Uke is more likely to change and escalate the attacks, Uke may be bigger/stronger and difficult to move, and Uke may have a knife in the other hand that he stabs you with. This is why failing to get off the line, however good you may be at unbalancing Uke (by whatever means), is incredibly dangerous. Once Uke is able to stop moving himself from the initial attack it becomes very easy to change. He can cut you even as he falls.

Don't give up and assume that it can't be done because you are struggling with it now. You see the vulnerabilities and therefore are able to improve. It is possible that there are things in Uke or Nage that you could correct. But it may also be that you are training correctly and simply need to stick with it longer.